In the awake of recent devastating landslides in Chittagong region that claimed more than 150 lives, experts predict that the country’s hilly region will face more landslides in future due to increased variability of rainfall caused by climate change.
“The intensity of rainfall will go up in the hilly areas of Chittagong in the days to come due to climate change…higher intensity of precipitation will occur in a shorter period of time, causing more devastating landsides,” climate expert Dr Atiq Rahman told UNB over phone.
Although the amount of rainfall may remain the same in the region in the next 30 years, he said, climate model shows that the amount of rainfall, which occurred in 10 days in the past, may take place within two days in the future, affecting the hill surface and causing more devastating landslides there.
Malik Fida A Khan, a deputy executive director of the Center for Environmental and Geographic Information Services (CEGIS), said the variability of rainfall is changing gradually in the country due to climate change.
“If we assess the average trend of precipitation, we will find its variability is increasing day by day. Rainfall is getting more concentrated. High intensity of rainfall is occurring in a short period. This concentrated rainfall is more dangerous as it triggers landslides,” he said.
Bangladesh is one of the most vulnerable countries to climate change due to its geographic location where high-intensity rainfall has become more frequent in the recent years.
According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the frequency of heavy precipitation events is increasing in South Asia, including Bangladesh, while light rain events are decreasing.
A 2014 study of Bangladesh University of Engineering and Technology (Buet) also shows that the highest increasing precipitation trend can be seen in the Chittagong Hill Tract (CHT) region in the days to come.
Hilly topography of this region along with elevation ranging between 600 and 900 metres above mean sea level contributes to heavy rainfall, the study said.
About the nature of the country’s hills, Dr Atiq said the stability of Bangladesh’s hills is very poor as most of them are created with clay, not with rock.
Since rain directly falls on clay-built hills due to deforestation and hill cutting, it affects the hillslopes and triggers landslides, he said, observing that the hilly areas of the Chittagong region that experienced high deforestation and hill cutting have counted huge loss in landslides this year.
Dr Atiq Rahman, executive director of Bangladesh Centre for Advance Studies (BCAS), suggested an immediate end to hill leveling and huge afforestation to stabilise hillslopes, aiming to prevent future landslides in the hilly region.
Noting that landslides depend on the nature of hills, Fida A Khan said when slopes of a hill are changed anyway, one kind of pressure is created inside the hill and cause landslides.
Blaming the development works that changed hillslopes in the CHT, he said if the nature of hills is changed due to unplanned settlement and agriculture landslides will certainly take place there.
Fida Khan stressed taking immediate measures to stop settlement on hills and check such agriculture that needs to make the hills clean aiming to avoid landslides in the future.
Over 154 people, including five army personnel, were killed as torrential rains triggered a series of landslides in southeastern hills last week.